I think it's quite possible. The economy has made the progress expected, the cuts were announced early, so there is nothing new coming there. The latest output figures are good, and as wages begin to creep upwards, people will be feeling a bit better off and won't want it all blown precipitately on another new Labour binge. (Balls has to go if they want to escape the association with reckless spending).
And there is still an almost total absence of policy proposals by Labour, let alone one with some idea of the expected costs and whether there will be countervailing cuts (to what?) or more borrowing (lead balloon). They still look utterly unelectable.
The mantra 'tax bonuses' is all well and good, but I don't think anyone could persuade the electorate that it produces a bottomless pit of money that will pay for everything (in the way that it's been waved around for all sorts of additional spending).
Labour has also said it won't be reversing coalition cuts. Which will be another reason to stick with the coalition parties, as it's backdrop for both main parties and current government, despite omnishambes at times, is the one that has done it.